New York Sen. Charles Schumer wants the government to investigate U.S. oil refiners’ skyrocketing profits, which he said are to blame for high gas prices.

“Something is rotten,” said the Democrat, speaking today at a gas station on Manhattan’s West Side.

He said refiners’ profits have more than doubled since last year. Meanwhile, the price of unleaded gas went up by almost 12 percent in just the two weeks ending May 6, topping $4 a gallon in New York.

The senator said he believes refiners may be fixing prices by cutting back on stockpiles — by keeping refining capacities to only 81 percent and through exports that diminish domestic availability.

In a letter to the Federal Trade Commission, Schumer demanded an investigation into record profits by major refiners.

The letter is also signed by Senate Majority Leader Harry Reid and three other Democratic senators.

Memorial Day weekend marks the start of the summer drive season, “and it ruins your vacation when you pull up to the pump and spend $80 to fill your tank,” said the senator. “It turns your stomach.”

He said that historically, refiners’ profit margins have been narrow. But in the past year, they’ve shot up.

Schumer said there’s evidence the spike may not be due to a supply-and-demand market dynamic, but that “illegal practices … could be punishing drivers.”

He did not name any companies, but said a probe should examine all of them, including the biggest five: Exxon Mobil, Shell Oil, BP, Chevron and ConocoPhillips.

Last month, President Barack Obama announced his effort to try to root out any manipulation of oil markets, with Attorney General Eric Holder and the Justice Department looking into a variety of reasons that could have spurred gasoline to $4 a gallon.